The present invention relates to a line head and to an image forming apparatus.
A line head is known as a device for forming (exposing) an electrostatic latent image on a surface of a photoconductor incorporated into an image forming apparatus of an electrophotographic system, such as a copy machine, a printer, or the like. The line head is provided with a plurality of light-emitting elements one-dimensionally arrayed on a substrate, and the respective light-emitting elements are driven through wiring lines patterned on the substrate. Light-emitting diodes (LEDs) and organic EL elements are utilized as the light-emitting elements of the line head. A light-emitting element array corresponding to this line head and an image forming apparatus are disclosed in, for example, Japanese Unexamined Patent Application Publication No. 11-274569.
In general, data lines and control signal lines are arranged according to the arrangement of light-emitting elements, in an organic EL panel used for the line head. Therefore, the length of the wiring lines reaches several tens of centimeters, which is likely to cause a build-up of static electricity and electrostatic breakdown to occur in circuits other than an input buffer. In particular, among the control signal lines, clock signal lines for sequentially selecting a plurality of light-emitting elements are disposed to be separated from other wiring lines, in order to reduce parasitic capacitance, so that static electricity is likely to build-up. Accordingly, electrostatic breakdown is more likely to occur in a circuit connected to the clock signal line than other wiring lines.